Unlike an existing internal combustion engine, an electric vehicle (e.g., HEV, PHEV, BEV, or the like) uses electricity as main power or auxiliary power and, to this end, a high voltage battery is mounted thereon to be used. At this point, a battery management system is a controller entirely managing the main battery, which includes measuring a state of charge (SOC) of the high voltage battery. The battery management system allows voltages necessary for driving and controlling the vehicle to be provided from the main battery to each component of the vehicle by performing controller area network (CAN) communication with a hybrid control unit (HCU), a motor control unit (MCU), and a generator control unit (GCU).
In addition, if necessary, the battery management system may protect the main battery by turning off a main relay or cut off voltages provided from the main battery to each component of the vehicle. When the battery management system independently determines that the main battery needs to be protected, or when there are requests from other controllers, the battery management system may turn off the main relay to cut off the voltages provided from the main battery to each component of the vehicle.
However, since controllers (HCU, MCU, GCU, and the like) do not share a request signal for turning off the main relay with each other, each of the controllers may not know whether the battery management system is requested for turning off the main relay by other controllers. For example, when the MCU requests to turn off the main relay from the battery management system during operation of the HCU in relation to the main relay, the main relay may be fused, since a current is supplied to the main relay due to the operation of the HCU, even if the main relay is turned off by the request by the MCU.
Due to the fused main relay, since the battery management system does not manage the SOC or the like of the main battery, overcharge or over-discharge of the main battery may be caused and the overcharge or over-discharge of the main battery may cause explosion of the battery and a danger of an electric shock to a driver.